package com.zhengtoudai.database;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

/**
 * Created by Administrator on 2016/8/5 0005.
 */

public class DBHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME="ztd.db";
    private static final int DATABASE_VERSION=1;
    public DBHelper(Context context) {
        //CursorFactory设置为null,使用默认值
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    //数据库第一次被创建时onCreate会被调用
    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS user"+
        "(_id INTEGER PRIMARY KEY AUTOINCREMENT,phone varchar(20),password varchar(20))");
    }

    //如果DATABASE_VERSION值被改为2,系统发现现有数据库版本不同,即会调用onUpgrade
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("ALTER TABLE user ADD COLUMN other STRING");
    }
}
